patent U.S. Pat. No. 6,353,707 discloses an electric heating device on base of the ribbon. The ribbon extends along the device and is bent in a plurality of locations, where the ribbon has an electro-conductive coating for mechanically strengthening and electrically shunting it in these locations. U.S. Pat. No. 6,353,707 describes also heating devices comprising an insulating rigid or flexible shell and a flat continuous heating resistance foil ribbon disposed inside the shell.
PCT patent Application WO 03/017721 A2 and U.S. patent application Ser. No. 10/367,742 on its base “Electrical Heating Device” disclose an electric heating device including a flexible resistance ribbon of special alloy composition with close limits of components, fastened to fiberglass or plastics net by glued tapes or spots, forming insert, which is incorporated in different plastics shells. It is described different structures of plastics heaters based on this inserts.